Control valve for air-brake apparatus



Sept. 28 1926. 1,601,590

W. ASTLE CONTROL VALVE FOR AIR BRAKE APPARATUS Filed March 24, 1926 6 Sheets-Sheet 1 INVENTOR William Astle ATTORNEYS Full Release & Chafjfiflj PO-Sl llOTl W. ASTLE CONTROL VALVE FOR AIR BRAKE APPARATUS Sept. 23, 1926., I 1,601,590

Filed Marsh 24, 1925 6 sheets sheet 2 INVENTOR Williamflstle ATTORNEYS Sept. 28,1926. 1,601,590

W. ASTLE CONTROL VALVE FOR AIR BRAKE APPARATUS Filed March 24, 1926 s Sheets-Sheet 5 A75 M J /68 6 9 I AMOS Dha a Release after Service /87 INVENTOR 97 William Astle ATTORNEYS Sept. 28 1926 1,601,590

W. ASTLE CONTROL VALVE FOR AIR BRAKE APPARATUS Filed March 24, 1926 6 Sheets-Sheet 4 42'. Emeryeng Pas'z'tz'nn. 62

#3 {Z 200 /Z 20.? A46 20/ 202 INVENTOR William Astle ATTORN EYS Sept. 28, 1926. 1,601,590

W. ASTLE v CONTROL VALVE FOR AIR BRAKE APPARATUS Filed March-24, 1926 6 Sheets-Sheet 6 5 1 .6. 5 A50 46 Seri/ zce Lap POSZtZ'O/TZ7Z 22 INVENTOR William Astle cations of the brakes.

Patented Sept. 28, 1925.

ra es lti...

AIR BRAKE COMPANY, OF WILMINGTON, DELAWARE, A CORPORATION OF DELAWARE.

CON TROL VALVE FOR AIR-BRAKE APPARATUS.

Application filed March 24,1926. Serial No. 97,015.

This invention relates to improvements in that type of air brake apparatus known as the Kunze-Knorr brake, in which a c01npound. brake cylinder is employed. One of these cylinders is what is known as a singlechamber cylinder, and in which a brake piston operates, air under pressure being admitted to said cylinder through the control valve for an application of the brakes. The other cylinder is what is known as a doublechamber cylinder, the two chambers being separated by a movable abutment or piston. This piston is also: connected to; the brakeapplying rigging or mechanism and comes into operation only in emergency applications of the brakes. One chamber of the double-chamber cylinder supplies air under pressure for service braking, said air passing into the single-chamber cyglinder for service applications of the bra es. This, chamber may be convem'ent-ly designated as, the service chamber. The other chamber of the double-chamber cylinder contains air under pressure which is used in emergency appli- This chamber may be conveniently designated as the emergency chamber.

The main object of this, invention is to improve the compound brake cylinder type of air brake apparatus.

Other objects of the invention are:

1. To provide means for producing uniform brake cylinder pressure for a given brake pipe reduction regardless of the ex tent of the brake cylinder piston travel.

2. To provide means operating automatically to compensate for brake cylinder leakage so that a given brake cylinder pressure will be maintained. l

3. To. provide means whereby air will be taken from the brake pipe to compensate for brake cylinder leakage.

4. To provide means to prevent automatic emergency applications of the brakes when there has been an equalization of pressures in the service chamber and in the singlechamber brake cylinder.

5. To provide a quick-release reservoir and means whereby when the control valve is moved to release position air from the quick-release reservoirwill flow to the brake pipe for a quick release of the brakes.

6. To provide a manually adjustable release-governing valve having a quick-release position and a. graduated-release position, the said release-governing valve in its quickrelease position co-operating with the main slide valve and the quick-release Valve to Secure a quick release of the brakes. The release-governing valve in its graduated-re lease position prevents the operation of the quick-release mechanism.

7. To. provide a graduated-release valve operating'to release brake cylinder pressure in direct proportion to the increase in brake pipe pressure.

8. To, provide an application valve which is controlled in its operations by the opposed pressure of the brake cylinder and the pressure in a control chamber.

9. To provide an emergency valve and an emergency brake pipe vent valve operating only upon a sudden and prolonged reduc-' tion in brake pipe pressure.

10. To provide means whereby an excessive brake pipe pressure will move the main slide valve into retarded-recharging and restricted-release position I '11. To provide means for temporarily connecting the brake pipe to the brake cylinder, upon a reduction offbrake pipe pressure for an application of the brakes, thereby securing a quick serial action of the control valves throughout the train.

There are other objects and advantages of the invention, all of which will appear hereinafter.

In the drawings:

Fig. 1 is a diagrammatic view of the control valve, showing the parts in full release and charging position;

Fig. 2 a view similar to Fig. 1, showing I the parts in service-application position;

Fig. 3 adiagrammatic view of a portion of a control valve, showing the parts in the position they assume in release after service;

' Fig. 3 a detail view of the release valve in release position;

Fig. 4 a view similar to. Fig. 2, showing the parts in emergency position;

Fig. 5 a view similar to Fig. 1, showing the parts in graduated-release position;

Fig. 5 a detail View of the graduated-release valve in release position;

Fig. 6 a diagrammatic view of a portion of the control valve, showing service lap position;

Fig. 7 a diagrammatic view similar to Fig. 6, showing the main slide valve in retarded-recharging and restricted-release position; and

Fig. 8 a diagrammatic view of the control valve, its associated reservoirs and the brake pipe and brake cylinder.

In order to simplify the description of the control valve and its operations, the various parts and the ports and passages will notbe specifically described except in connection with the description of the various operations of the valve.

In the diagrammatic View Fig. 8, A designates the control valve; B the single-chainber brake cylinder; C the service chamber; D the emergency chamber of the doublechamber cylinder; E the brake pipe; F the quick-release reservoir; and G the emergency reservoir which is in direct communication with the emergency chamber D.

i In the control valve is formed a main valve chamber 1. In this chamber is arranged a main release piston 2 and a service piston 3. The release piston, as shown in the drawings, is at the left-hand end of the main valve chamber and the service piston is in the right-hand end of said chamber. These two pistons are rigidly connected together by a central valve stem 4. extending through the main valve chamber. The release piston operates in a main brake pipe chamber 5 and the service piston reciprocates in a chamber 6. The pistons 2 and 3 serve as movable abutments which separate the chambers 5 and 6 from the main valve chamber 1. Inthe main valve chamber is formed a main valve seat 7 on the parts in which slides the main slide valve 8,'said valve being connected to the piston stem at as will be hereinafter described.

mit the graduating valve to move to lap position without moving the main slide valve. On top of themain slide valve is arranged a graduating valve 9, said valve beingdirectly connected to the valve stem 4: and moving with it. A service lap spring 10 is arranged to be compressed when the main slide valve is moved to service posi tion, said spring exerting its force to move the graduating valve to service lap position, Surround ing the piston rod 4 adjacent the service piston is a charging stop spring 11. This spring serves to stop the main and graduating valves in normal charging position and permits them to move to retarded-recharging and restricted-release position when there is an excessive brake pipe pressure operating on the release piston 2, as will be more fully hereinafter described.

An application valve H cooperates with the main and graduating valves to control proportion pre 'and the main slide valve.

valve communication between the service chamber C and the single-chamber brake cylinder I5. \Vhen the main and graduating valves are moved to service position the application valve is moved to open communication between the service chamber and brake c linder B for a service application of the brakes. When the desired brake cylinder pressure has been built up in the brake cylinder B the application valve is moved by brake cylinder pressure, plus the energy of an application valve spring, to lap position, thereby closing communication between the chamber C and the brake cylinder B. The application valve operates in such manner that pressure will be built up in the cylinder B in direct ratio to the brake pipe reduction,

regardless oi the length of brake cylinder piston travel in the cylinder B. If this piston travel 18 short, that is to say below the standard set in the apparatus, the excess pressure from chamber C will be passed back to the brake pipe through the operation of the application valve. If the piston travel is long, that is to say greater than the standard set for the apparatus, and the pressure in cylinder 13 is not as great as the ratio set for the apparatus, the application valve, ro-operating with the graduating valve in service la) osition will admit l. 7

bra re pipe air to the cylinder B until the pressure is at the desired ratio to the re duction in brake pipe pressure.

.9 'raduated-release valve I controls the release of brake cylinder pressure in direct to the increase in brake pipe re. This graduated-release valve cooperates with the application valve and the main slide valve in graduated-release operations. This graduated-release valve is idle operations when the release-governing 'release position the release of brake cylinder pressure takes place entirely through the graduated-release valve, said valve cooperaing. however, with the a pplication valve The application is so constructed that brake cylinder pressure in cylinder B will be built up in direct ratio to the brake pipe reduction. Usually this ratio is two-and-one-halt to ODG,--tillt is to say, for a ten-pound brake pipe reduction a twentylive-pound. pressure will be built up in the brake cylinder. 11s graduated-release valve is constru in such manner as to maintain the same ratio 'of. pressures in release operations; that is to say, a tenpound increase in brake pipe brake cylinder pressure, these two pressures lVhen Hit) ill)

gency chamber D is incrcaseih for a release of the brakes the steel-release valve will be moved to release position. at the same time the main slide valve and the application valve will move to release posit" n q 1 q 1- 1 M -Jh' A 11 am will i ow into tie Diane c nnuel Chill ot the graduated-release valve.

A lorelease valve J is provided, which 01 crates when the release-governing valve 1s 1r quick-release position. to place a quickrelease reservoir in communi ation with the brake pipe to quickly raise the brake pipe pressure and thussecure a quick release of the brakes throughout the train.

An emergency valve mechanism K controls the exhaust of pressure from the service chamber C for emergency applications of the brakes. This emergency mechanism will operate only upon a sudden emergency reduction of brake pipe pressure. An equalization valve ll co-operates with the emergency mechanism operating when the brake emergency operation when there is an equalization of pressures in the brake cylinder B and the service chamber C. This equalizing valve also prevents the emergency mechanism operating when the brake pipe pressure drawn down below the pressure at which chamber C equalizes into cylinder B, so that an emei ncy application cannot be secured without an emergency reduction in brake pipe pressure.

The quick-service valve lil operates to temporarily connect the brake pipe to the brake cylinder upon a reduction of brake pipe pressure. This is for the purpose of se nring the quicl; serial action of the control valves throughout the train.

The release-governing valve mechanism ll controls the rate of of brake cylinder pressure. This valve has a graduatedrelease position and a quiclorelease position as hereinbefore described.

Uhargng.

retarded-charging position upon an excessive charging pressure. From chamber 5 air flows through passage l l past check valve 15 to passage 16, this later passage leading dirctly into the i: .in cl a nher i. In the norms. release position of the main slide valve a charging port 17 therein is in register will a port 18, said port being connected to a passage 19 which leads to a small chamber 20 in which is arranged a check valve 21. Air flowing into chamber lifts valve 2i and passes into a passage 22. Passage :22 leads to a port 23 in the main slide valve seat. In the main slide vs 2 is porand passage which, in the release position oi the main slide valve, connects port 23 to is connected to a passage 26 which leads to the ser ice chamber C so that brake pip air will flow from the main brake pipe cham- 5 through the ports and into the service chamber C.

The charging passage connected by pssage 527 to brake pipe chamber 28 01 the emerge-ne valve. this chamber is arrange emergency vznve pistor 29 l inwardly to the limit or" its Connected to the passage 22 is a passage 32" 3 a 4.. vincn l ads nto the emergenc valve chain- 1 u 2 I 1 r: blElKO DL G till. \VLL D53 bllill 6ft 1 .L L c said chamber the pressures will 1 her 31. so {13L into emergency reservoir 33, 1 communication all times through valve chamber 31 is reservoir bei with the chamber 81 at passage lair flowing into the chamber C through will force the cine cy brake IlSeOl'l 35 toward the J as viewed. in the drawings, to the -s moven This movement of the uncover a port 36 which leads hcr {l into the emergency chamber D, nd air will flow from G into cored to chamber l) is the which augments the capacity or t chamber D. Connected to port is into ch mber into said cl on opposite SlCl5 of Connected to the r 5 and in open quick-re is mount: Brake pipe pressure in cl amber 5 operates port 45 in the main slide valve seat, and

against one face of said plunger. In said plunger face is formed a port 4L0, so that air will flow from chamber 5 throi gh said port into chamber &1 on the opposite side of said plunger. Chamber 4:1 is connected by pas sage 42 to a port l3 in the main slide valve seat. In the main slide valve formed a long cavity 44 which connects port L3 :0 21 said port is connected by a 4-6 to the quick-release reservoir F. Cavity istalso connects port l3 to a port 17 which is coir nected directly to quick-release chamber as for a purpose which will hereinafter appear. In the passage 46 is arranged a check valve 49 which seats toward the port and prevents air passing from the reservoir F back to said port. Connected to the passage 46 beyond the check valve s9 is a pa age 50 which leads to the release pressin'e cl iber 51 of the graduated-release valve structure, so that quick-release reservoir air will be always present in said chamber 51. The passage 37 is connected by a pas age 52 to the actuating chamber of the graduated release valve structure so that emergency chamber pressure will be a! vays present in said actuating chamber. The pressures in chambers D, 6 and 53 are always em The charging passage 13 is coni'iec d with a passage 5% which leads into chamber above the equalizing valve piston 56. Passage 54 also leads into the equalizing val e chamber 57 so that brake pipe pressure will be always in said chamber and wi l also operate on the upper side of the equalizing valve piston and hold the equalizing valve in closed position, except as hereinafter de scribed.

An excessive brake pipe pressure in chamber 5 will move the main slide valve inwardly to restricted-charging position. In this position of the valve, restricted port 17 will be brought into register with the port 18. This will result in a delayed charging of the chamber C and also of chambers D, 6 and The cavity a l will be moved out of register with a port 45, thereby stoppin the flow of air to the quick-release re ervoi F and to the chamber 51 of the gradii release valve structure. The port and sage 24c in the main slide valve is provided with extensions at its ends to in 'itain communication between ports and 25 in re tarded-charging position of the main slide valve. \Vhen there has been an equalization of pressures on opposite sides of the release piston 2 the charging stop s ring will return the main slide valve to normal charging position, in which the charging og ieration will take place as hereinbetore described. When the pressures in all of the chambers have been equalized with the normal running brake pipe pressure, the system is fully charged.

Service application.

A service application of the brakes is brought about by a service reduction of brake pipe pressure in the usual manner. A service reduction of brake pipe pressure in chamber 12 will result in a corresponding reduction of pressure in the brake pipe chamber 28 of the emergency valve and in the main brake pipe chamber 5. The reduction of pressure in chamber 28 will result in a movement of the emergency valve toward the left as viewed in the drawings, by reason of the undisturbed pressure in chamber 31. The emergency valve will move outwardly until the spring-pressed service stop 58 of the emergency piston contacts with the end of the valve casingtf The service stop spring 60 will be slightly compressed and the emergency piston and the emergency valve. will continue to move until the service stop collar 58, at the righthand end of the emergency valve stem, engages the yoke T2 of an emergency lever 73. The lever 73 is held yieldingly against inward movement by spring 74 which holds energeney check valve 75 to its seat; The yoke 72 and the spring 60, therefore, stop the emergency valve in service position upon a service reduction of pressure in chamber 28. This stops the emergency valve in position to uncover port 59 in the emergency valve seat. Air will flow from chamber 31 through port 59, passage 61, past check valve 62, through passage 62-} to port 64rin the main slide valve seat. The service reduction of brake pipe pressure in chamber 5 results in a movement of the main slide valve toward the left as viewed in the drawings, until the service stop 65 formed on the outer side of the release piston 2 contacts with the abutment 66 formed in the valve casing. The spring-pressed plunger (37 will engage the outer wall of the valve casing and the service lap spring will be compressed. The undisturbed pressure in chamber 6 will force the service piston 37 toward the left until the stop 65 engages the stop shoulder 66. The lost motion between the valve stem and the main slide valve will be first taken up and then the main slide valve and the graduating valve will be moved into service position (F 2). The movement of the main slide valve into service position causes the cavity 68 in the main slide valve to place port 64: in communication with port 69. Port (39 is con nected to passage '70 which leads to a control chamber 71 of the application valve H. Through the ports and passages just described the emergency valve chamber 31 and the volume reservoir 38 are connected to the control chamber 71. Air will. continue to flow into the control chamber until the pressure in chamber 31 has been reduced will prevent the flow of air from chamber Q I w .Q 31 to the control chamber. The volumes or chambers 33 and are so proportioned with respect to thevolumeo'f chamber 71 that there will be built up in chamber 71 the pressure which is desired to secure in the brake cylinder for a given bra re pipe reduction. This is usually at the ratio of two-and-one-half to one so that a ten-pound pressure reduction chamber 28 will result in building upa twenty-fivepound pressure in the control chamber 71 before the emei ncy valve is moved back to close the po 59. The pressure established in chamber 71 preuetermines the amount of brake cylinder pressure builtup in the brake cylinder.

d' hen the main slide valve and the grad valve are in service position port A main slide valve reg ers with port .25. in the graduating A cavity 74 valve registers with port- 75 and connects sa d port with a port '78 i the main slide This latter port is in register with 79 which is connector to passage ch leads to a small valve chamber in which is a ball check valve which is the main application valve. onnected directly to a brake .re iamber 83 of the application val e structure. The main appli ation val e 82 is normally seated and closes commu lcation between the hamber 81 and the chamber and this valve is opened by he sure in chamber 71, as will be heredescribed.

The application valve structure comprise two parallel diaphragms a and h; spaced a suitable distance apart and secured around the n arginal edges in the valve casing. These diapnragms are shown in the drawings as horizontally arranged. Between the diaphragm a and the lower wall 01 the casin is formed the control chamber 'l'l. tween the diaphragm b and the upper wall of the valve casing is tormed the brake 'linder pressure chamber 83. Between ti c o diaphri gms is formed a release chamber The central portions or the diaphmgms are supported by rigid central c. iping members and the supporting members of the two diaphragms abuttogether so that the two diaphragms move up and downtop'etner in response to variations of pressures in the chambers 71 and 83. The upper diaphragm h carries a central upwardly e eend'ng stem 85 which is adapted toengage a ce tral abutment 86 to limit the upward movement or the diaphragms. The lower diaphragn a carries a central depending stop 87 which is adapted to engage the lower wall of the chamber 71 to limit the downward movement of v the d-iaphragms. A valve operating lever 88 :is mounted in the chamber 83, said lever being pivoted at one end on a post 89 and being pivoted midway its ends at 90 to the central stop stem 85.

,lTl1e'iree=encl ot this lever is adapted to enthe lower end of a pin 91 which extends from chamber 83 upwardly and into engagement with the check valve 82. When pressure is built up in the control chamber the diaphragms are moved upwardly and the lever 88 is swung on its pivot to open the valve 89, thereby permittingair to flow from chamber 81 -;into the chamber '83 until "the pressure in said chamber is substantially equal to the pressure previously built up in chamber 11. The pressure in chamber 83 will then equal the desired brake cylinder pressure.

The brake-cylinder pressure chamber 83 is connected by a passage .92 to the singlechamber brake cylinder B. Air will, therefore, flow from chamber 83 into the brake cylinder B. lWhen the main and graduating valves are in service position and the main application valve is open, air will .flo-w from the service chamber G into the chamber 83 and then intoabrakecylinder 13 until the pressure in said bralzecylinder and in cham- 88 is substantially equalized with the pressure in chamber 71, whereupon the diaphragm structure will move downwardly and the valve 82 will seat and :stop further flow of air from chamber G. Air will continue to flow into the brake cylinder until the required pressure is built up therein, regardless of the length of piston travel. The application valve 82 will close when the desired brake cylinder pressure has been built up in chamber 83 and, of course, this will occur regardless of the length of piston travel in the single-chamber brake cylinder chamberv B. Y

As the pressure in chamber C is reduced, the emergency brake piston will move toward the left as Viewed in the drawings, and disconnect port 36 from chamber C. The piston 35 will be moved by the pressure in the emergency chamber 1) and said piston will continue to move toward the left until there is a substantial equilibrium between the opposed pressures on the piston 35. The movement of the piston 35 will reduce the pressure in chamber D and consequently in chamber 6, and also in theactuating chamber 53 of the graduated-release valve. The pressure in chamber 6 will be reduced to a substantial equality with the brake pipe pres sure in chamber 5, with the result that the service lap spring 10 will move the graduating valve to lap position, thus cutting off communication between chamber C and the brake cylinder B. y

In the release chamber 84: is pivoted a horizontally arranged lever 93, said lever being pivoted at 94: between its ends to the central stem of the diaphragm structure. The free end of this lever extends through a slot 95 in the valve casing and is connected to a main release valve 96. This release valve operates in a chamber 97. The chamber 83 is connected by a passage 98 to a port 99 in the release valve seat. The release valve is formed with a cavity 100 which, in the release position of the valve 96, connects port 99 with the slot 95 and to the chamberSL so that in the release position of valve 96 brake cylinder pressure may flow from the brake cylinder B and chamber 83 into the chamber 84:. Passage 80 is connected by a passage 101 to a port 102 in the seat of the release valve. In the normal or lap position of the release valve 96 port 102 opens directly into the release valve chamber 97. When the release valve is moved upwardly through the upward movement of the diaphragms a and 6, port 102 is closed so that said port will be closed when the main application valve 82 is open; but said port 102 will be open to the chamber 97 whenever the application valve 82 is closed. A spring 103 bears on the valve 96 and returns it to its normal or lap position. When the release valve is moved upwardly the spring 103 is compressed so that said spring tends to return the release valve to lap posi tion when the application valve 82 is open and the force of said spring assists the pressure in chamber 83 in moving the dia-} phragms and the release valve back to normal position. The chamber 97 is connected by a passage 1041 to the brake pipe passage 13 In the event that the brake piston in cylinder B moves less than the normal or standard piston travel, the desired brake cylinder pressure will be built up in the cylinder B and in the chamber 83 before the pressure in chamber 6 has been sufficiently reduced to permit the graduating valve to be moved back to lap position, with the result that it would be difficult to secure a release of the brakes because 01 the high pressure in chamber 6. With the main and graduating valves in service position air may continue to flow from chamber C through passage 101 and ort 102 into chamber 97, when the release valve 96 has been moved to normal position by the pressure in chamber 83 and by the force of the spring 103. From chamber 97 air may flow back through passages 104 and 13 to the brake pipe so that the excessive pressure in chamber C will be passed back to the brake pipe until the graduating valve is moved to lap position, thus cutting off communication between ports 25 and 79.

A supplemental application valve chamber 105 is provided with a supplemental application valve 106. This valve is in the form of: a ball check. Chamber 105 is connected di rectly to the chamber 83 and the valve 100 seats toward said latter chamber. A pin 107 engages the valve 106 and its lower end projects into the chamber 83 and isadapted to be engaged by the upper end of the central stop stem 85. lVhen the lever 88 is moved upwardly by the pressure in chamber 71 valve 106 is lifted from its seat, so that the main application valve 82 and the supplemental application valve 106 are opened by the upward movement of the lever 88. Chamber 105 is connected by a passage 108 to a port 109 in the main slide valve seat. The main slide valve is formed with a port 110, which, in the service position otthe main slide valve, registers with port 109. The graduating valve is formed with a port 111 which, in the lap position of the graduating valve, registers with port 110. Ports 110 and 111 serve to connect port 109 to the chamber 1. When the main slide valve is in service position and the graduating valve is cylinder B has a longer travel than is normal or standard for'the apparatus the pressure in chamber 1), and consequently in chamber 6, will be sufliciently reduced to permit the graduating valve to be moved back to lap position before the brake cylinder pressure in B and in chamber 83 has equalized with the pressure in the control chamber 71. The result of this will be that the main and supplemental application valves 82 and 106 will be held open. The movement of the graduating valve to lap position will cut oil chamber C from application valve 82 but will place the main valve chamber in communication with the supplemental application valve 106. Brake pipe air will therefore flow from chamber 1 past valve 106 into chamber and into the brake cylinder B until the desired pressure has been built up therein. When the desired pressure is secured the diaphragm structure will move downwardly and valves 82 and 106 will seat. As pressure is drawn from chamber 1 air will flow from chamber 5 through passage 14, past check valve 15 and through passage 16 into the chamber 1, should the pressure in chamber 1 be reduced below the brake pipe pressure in chamber 5.

The control chamber 71 is connected by a passage 112 to a chamber 113 below the equalizing piston 56, so that a pressure equal to the desired brake cylinder pressure will be always present under the piston 56 and opposed to the brake pipe pressure in, chain-- ber 55 above the equalizing piston. hen the pressures ofchambers 31 and 33 have been equalized into chambers 71 and 113 and the brake pipe pressure has been reducer in chamber 28 to an equality with the said equalized pressures, the "'zaximum service application pressure has been secured. c* linder B andthe pressi-ires in chambers and 113 opposite sides of the ecualis piston have been equalized. A re brake pipe pressure below this eoualization would i move valve to emergency -v valve into the emergency valve chamber 81. In passage 116 is arranged a check valve said valve seating toward'the passage St so that air pressure cannot flow tlzoieni port 115 to said passage but may flow in the opposite direction past said chec valve. i l hen the equalizing piston has been moved upwardly the equalizing valve 111- uncovers port 115, thereby permitting a flow of air from chamber 31 and connecting volume chamber 33 through passages 82 and 119.

with chamber 57. From chamber 7 air may flow through passage 51 to passage 18 and thence to the bra e pipe. It is clear, therefore, that when brake plpe pressure is reduced below the pressure in chamber 113 air will flow from chambers 91 and 83 bacl: to the brake pipe, thus maintaining the pressures on opposite sides of the emergency Jiston 29 substantially equalized. This will prevent the emergency valve moving to emergency position. The pressures in control chamber 71 and chamber 113 cannot be drawn down with the brake pipe under the conditions just set forth, because the check valve 62 prevents air from said two cham bers flowing into the emergency valve chamher. Under the conditions specified the emergency valve will be in service position and port 59 will be uncovered. The 1min slide valve will be in service position and the graduating valve will be in service lap position. lhe brake cyclinder pressure will be maintained so that pressures in chambers 71 and 83 will be substantially equal.

When the main slide valve moves to service position it uncovers port 118 and said port is connected by passage 119 to a small chamber 120. Chamber 120 is connected to a small chamber 121 by passage 122. 1n the chamber 121 is arranged a quick-service valve 123 said valve seating toward the chamber 120 and preventing pressure passing from 121 into chamber 120. When port 118 is uncovered brake pipe air will flow from the main valve chamber 1 into chamher 120 and will unseat valve 123 and flow into chamber 121. From this latter chamber air may flow through passage 12 1 into passage 92 and thence into the brake cylinder pressure chamber 83. The intlowing braite pipe air may also flow through 3assage 92 directly into the brake cylinder 11.

This permits a certain quantity o1: brake pipe air to flow directly to the brake cylinder immediately upon the opening of port 118. This flow of brake pipe air to the bra-lie cylinder will continue for short time and the valve 123 will be seated as soon as there is a certain amount of pres sure built up in the brake cylinder.

The chamber 121 is formed in the lower part of the valve casing of the quick-service valve mechanism M. At the upper end oi. this valve casing is formed a chamber 125 and said chamber is connected by passage to the chamber 121. In the chamber 1 a vertically movable piston 12' large area compared with the area ot the 23. liston 127 is torr ed with a central depending tubular stem 128. G11 the lower end of this stem is formed a piston 129 which is smaller in area than the piston 12?. Piston 129 reciprocates in chamber 121 and its under side is exposed to the pressure in said chamber. The lower side of the piston 129 is formed with a-depending central extension which is adapted to contact with the upper side of the valve 123 at the center there and to serve as a means for holding said valve on its seat. Within the tubular eXtension 128 is arranged a coil spring 190, the lower end of said spring engaging the picton 129 and the upper end thereof engagin C) the upper wall of the valve casing. :1 .o pistons 127 and 129 are connected to the casing in which they reciprocate by the tier:- ible bellows 131 which form air-tight connections and prevent leakage of air around said pistons. Then the valve 123 is opened by brake pipe pressure in chamber 120, the pistons 129 and 127 are moved upwardly slightly. Air will flow from chamber 121 through the sassage 126 into the chamber 125. The piston 12'? is very much larger in area than the piston 129 so that a comparatively light pressure in 125 will force the pistons 12'? and 129 downwardly to seat the valve 1.13. This will stop the flow of brake pipe air to the brake cylinder. The pistons 129 and 127 may be properly proportioned to permit the desired flow of air from the brake pipe to the bralze cylinder at the beginning of each brake ap alication. This fill fill

venting of brake pipe air to the brake cylinder assists in the quick serial action oi: the control Valves throughout the train.

Service Zap position.

When the pressures in chambers D, 6 and 53 have been suiliciently reduced by expan sion, due to the movement of the piston the service lap spring will move the pisten 2 and the graduating valve 9 to lap posiion as shown in Fig. 6. Cavity 77 of the graduating valve will be. moved out of register with port 76, thereby interrupting the flow of air from chamber B to the application valve chamber 81 and to port 1052 of the release valve 96. The reduction of pressure in chamber 53 will permit the undisturbed pressure in release pressure chamher 51 to lift the diaphragm structure and the graduatedrelease valve, but this movement will bean idle one. The graduatedrelease valve has no function in the brake application operation of the control valve.

Release after serviceguic a release.

To effect a releas of the brakes utter a service application, the brake pipe pressure must be. increased in the usual manner through manipulation of the engineefis brake valve. The increased brake pipe pressure will flow through passage 13 into chant her 28 and force the emcrgency piston and the emergency valve to their inner position. The brake pipe pressure will also How through passage 13 into main brake pipe chamber 5 and force the release piston 2 and the main and graduating valves into normal release. and charging position, as shown in Fig. 1. A collar 132 on the main valve stem will engage the inner end 133 of a tubular abutment 134 which surrounds the valve stem. l Vithin the tubular abutment is arranged a charging stop spring 11. One. end of this spring bears against the end wall 133 of the abutment, its other end bearing against a tubular rigid stop 135 which is 'rarried by a rigid cross wall 136 and extends into the tubular abutment. The inner end of the stop 135 is formed with an upwardly extending flange which is adapted to be engaged by an inwardly turned flange carried by the end wall 13? ot the tubular abutment. These two liangcs are adapted to engage each other, the flange on the stop limiting the inward movenrat oi the tubular abutment under the force of the spring 11. lVhcn the piston 2 is forced inwardly to release position by a normal rate of rise of brake pipe PI'GSSL'UJQ, the spring 11 will stop the main and graduating valves in normal release and reservoir charging position but will yield under an abnormal brake. pipe pressure in chamber 5 to permit the main slide valve to move to retarded-recharging chamber 138.

and restricted-release positon, as will be hereinafter described.

In the valve casing is formed a main brake cylinder exhaust chamber 138 and this Cl12Lll1- her is connected through passage 139 to a large atmospheric port 140. A. releasegoverning valve 141 is arranged in chamber 138 and closes communication between that chamber and the exhaust port 140. A spring 142 normally holds valve 141 on its seat. Below the valve 141 is arranged a vertically movable pin 143, the upper end of said pin being adapted to engage the lower end of the valve. Below the pin 143 is arranged a manually operable rod 144 which is formed with a recess 145 and the cam'surface 146. This rod is adapted to be moved outwardly to quick-release position and to be moved inwardly to graduated-release position, the pin and slot 14. serving as means to limit the in and out movements of the rod 144. in the quick-release position of the rod 144 cam 146 engages the pin 143 and forces it upwardly against the valve 141 and lifts said valve from its seat. This places chamber 138 in direct communication with atmosphere through the passage 139.

la the release position of the main slide valve the control chamber 71 of the application valve is connected by passage 70 to port 69 ot the main slide valve seat. A cavity 148 of the main slide valve connects port 69 to a port 149 in the main slide valve seat and said port is connected by passage 1 to Air from the control chamber 71 will therefore How to the atmospheric port 140. As the pressure in chamber 71 is reduced the brake cylinder pressure in chamber 33 will move the diaphragms a and Z) downwardly and carry the main release valve 96 to release position and. connect port 99 through cavity 100 with the release chamber 84-, so that brake cylinder pressure will 'flow from the brake cylinder B and the chamber into the rel/e chamber 84. The dia- Or) phragms a and Z) are of the same area so that pre ure flowing into chamber 84 will have no ect upon the diaphragm structure.

From enamber 84 air will flow through the release PiSSHgB 151 into passage and thence, as previously described, to atmos-' phere through chamber 138 and atmospheric port 141). hi the passage 151 is arranged a check valve 152 which seats toward the chamber 84 and prevents the flow of air from passage 70 to said chamber.

ll hen the main slide vaive is in release positirm cavity 44 thereof ronnects port 43 to port 47. Air then may flow from chamber 41. through passage 42, port 43, cavity 44, port 47 to the quick-release chamber 48. This will reduce the pressure in chamber 41 and permit brake pipe pressure in chamber 5 to tore the quiclerelease plunger 39 inwardly. The plunger 39 is connected to one arm of a quick-release lever 153 which is mounted in the brake pipe chamber 5. The other arm of this lever is adapted to engage a quick-release valve 154 and lift it from its seat. said valve being normally held seated by a spring. The valve 154 is arranged. in a chamber155 and said chamber is connected by a passage 156 to a chamber 157. Tn this latter chamber is arranged a check valve 158 which seats downwardly and norn'ially closes a passage between chamber 15? and a chamber 159. Chamber 159 is connected by passage 160 to the passage 46 which leads to the q11ickrelease reservoir'F. When the quiclerelease valve 154 is raised, air may flow from the reservoir F past check valve 158 through passage 156,

past check valve 154 into chamber 5 and and then through passage 16 into the main slide valve chamber. From chamber 1 air will pass through the charging ports as hereinbefore described.

lVhen the pressure in chamber 48 has equalized with the pressure in chamber 41 and in chamber 5, the quick-release plunger will be moved back to its normal position by the spring 161 .and the quick-release valve 154 will close. The pressures in chambers 5, 41 and 48 will equalize through the leak port 40 formed in the quick-release plunger. ie size of the chamber 48 will determine length of time that the quick-release .ve 154 remains open and consequently will determine the amount of quick-release reservoir air that will flow to the brake pipe and to the main valve chamber 1.

ll hen the main slide valve is moved to service position a cavity 162 therein will connect port 47 to port .163. This latter port connected by passage 164 to a small chamber 165. In said chamber is arranged a check valve 166 which is normally seated by spring 167. This valve controls a passage 168 which leads to an atmospheric port 169. The release-governing rod 144 is formed with a cam 170which is adapted to engage a pin 171 and force it upwardly u" en the release-governing rod is moved oritwardl to quick-release position. The pin 171 engages the lower end 01' the valve 166 and t rces it upwardly from its seat thereby ope ing chamber 165 to atmosphere. ll hen port 4'? is connected to port 163. as

jut described, the air in the quick-release er 48 will flow to atmosphere through port 169. i ive Jrake pipe pressure in chamber 0 will move the main slide valve inwardwill be connected to the passage 148 through a restricted release port 149. Cavity 148 will be in register with port 69 of the main slide valve seat, so that brake cylinder pressure from the release chamber 84, and control chamber pressure, may flow through passage 70, port 69, cavity 148 of the main slide valve. restricted release port 149 and passage 150 to atmosphere, as hereinbefore described. hen there has been an equalization of pressures on opposite sides of the release piston 2, the charging stop spring will return the main slide valve to normal release position in which position the normal release operation will take place as here inbeiore described,

Release after seroz'cegmdua ted release.

T hecontrol valve is adjusted for graduated-release operations by moving inwardly the release-governing rod 144 to the position shown in Fig. 5. The inward move ment of this rod will permit the valves 141 and 166 to be seated by their springs, thus closing communication between the chambers 138 and 165 and atmosphere.

To effect a graduated-release of the brakes the brake pipe pressure must'be increased in the usual manner a predetermined amount, and the increased brake pipe pressure must be less than the full running pressure or full charging pressure.

The increased brake pipe pressure will move the parts to release position precisely as described under the heading Release after service-Quick release. The chamber 41 will be connected to the quick-release chamber 48 in the release position of the main slide valve precisely as hereinbefore described, but the quick-release plunger will not be operated to open the quick-release valve, because chamber 48 will be charged with air at brake pipe pressure. hen the niai-nslide valve is moved to service position the air in chamber 48 cannot escape to atmosphere because valve 166 is closed. The control chamber 71 will be connected to passage 150 through cavity 148 in the main slide valve. Valve 141 is closed so that air cannot pass from chamber 138 to atmos phere. Chamber 188 is connected by passage 172 to the brake cylinder pressure chamber 173 of the graduated-release valve structure, so that air will flow from the control chamber 71 into the brake cylinder pressure chamber 173.

The graduated-release valve structure comprises an actuating diaphragm 0; an equalizing diaphragm (Z; and a release diaphragm 6. These diaphragms are suitably mounted in a casing and are parallel with each other to form a series of chambers. The diaphragm (Z is larger in area than the actuating diaphragm c for a purpose which will hereinafter appear. Between the diaphragm c. and the upper wall of the valve casing is formed the actuating chamber 53. The brake cylinder pressure equalizing chamber 173 is formed between the actuating diaphra m c and the equalizing diaphragm d. Idetween the diaphragms (Z and e is formed a retention chamber 174, the function of which will hereinafter fully appear. Between the release diaphragm e and the lower wall of the valve casing is formed the release chamber 51. The central supports of the diaphragms are in close engagement with each other so that the diaphragms move up and down together, or substantially so, in accordance with the variations in the controlling pressure in the chambers of the diaphragm structure. The release diaphragm e carries a downwardly extending release stop 6 and the actuating diaphragm carries an upwardly extending central stop 0', said stop being formed on the upper end of a central stem. These stops limit the up-and-dow-n movements of the diaphragms. In the actuating chamber 53 is arranged a lever 175. One end of this lever 'ivoted on a rigid post secured to the wall of the actuating chamber, and the other end thereof is connected to a valve rod 176. Intermediate its ends the lever 175 is connected to the upwardly extending stop stem 0 so that the lever will be swung up and down by the up-and-down movements of the actuating diaphragm. On the lower end of the valve rod 176 is mounted a graduatedrelease valve 177 and said valve is held in its normal, inactive or non-release position by a spring 178. y

As hereinbefore pointed out the reduction of pressure in chamber 53, due to the expansion'of the air in chamber D, will permit the undisturbed pressure in chamber 51 to raise the diaphragm structure and the valve 177, therebyplacing the spring 178 under tension. This will be an idle movement of the graduated-release valve 177. As pressure flows from chamber 71 into'the equalizing chamber 173 the downward force exerted by said pressure will tend to move the dia phragm structure and the graduated-release valve downwardly. Pressure will continue to build up in chamber 173 until the downward force exerted on the diaphragm 03, plus the pressure in chamber 53 operating on the diaphragm 0, is suflicient to overcome the pressure in chamber 51, and move thevalve to release position, as shown in Fig. In this position of the valve 177 chamber 173 will be connected by passage 179, and cavity 180 of the valve 177, to an exhaust port'181 in the seat of valve 177. Port 181is con nected by passage 182 to port 183 in the seat oithe emergency valve 31. In the emergency valve is formed a long cavity 18% which, in all positions of said valve-except the emergency position, connects port 183 to an atmospheric port 185. In the release position of the graduated-release valve 177 air will therefore flow from the control chamber 71 through the ports and passages just described to the equalizing chamber 173.

hen the pressure in chamber 71 has been reduced the brake cylinder pressure in chamber 83 will move the diaphragms a and b and the releasevalve 96 to release position and cavity 100 will connect the chamber 83 through passage 98 to the release chamber 8st. From the said chamber 81 air will pass through passage 151 into passage 70 and then through the ports and passages hereinbefore described into the chamber 173, and thence to atmosphere through atmospheric port 185 in the emergency valve seat.

The retention chamber 174 is connected by a passage to a port 186 in the seat of the graduated release valve 177. Exhaust port 181 is connected by a restricted passage 186 to the retention chamber 174; lVhen the valve 177 is in release position passage 179 and port 186 are connected to the exhaust port 181 by the cavity 180 of said valve. .riir may then flow from chamber 173 through port 186 into the retentionchamber and also through port 181 into passage 182 and. thence to atmosphere tl'irough .the port 7, as hereinbefore described. Pressure will build up in chamber 174 while the valve 177 is in release position and this pressure will exert an upward pressure on the equalizing diaphragm (Z and tend to balance the downward force exerted on the said diaphre by the pressure in the chamber 173, and to that extent assist the pressure in chamber 51 in moving the valve 177 back to nen-release position.

The increased pressure in the main valve and 18 and thence through the con -ssages as hereinbeiore described, the charging port and passage 2 ain slide val e and thence through A and passage 26 into the chamber C, so that the pressure in chamber C will equalize with the'incerased brake pipe pressi The increasing pressure in chamber C will force the piston toward the chamber D and increase the pressure therein, and this will result in an increase of pressure in char b 6 and in chamber 53. The increase pressure in chamber 6 will be subeta tia y equal to the increased brake pipe r L e in chamber 5. The increased pres-- c in chamber 53 will not be suilicient to 'on. the in po mo the graduated-release valve to release 173 will cause the diaphragm :air from the brake cylinder will flow to "atmosphere as described. Air Will continue to flow from the brake cylinder and from the control chamber to atmosphere until the pressure in chamber 174 has been built up through the port 186 to a suficient degree to assist the undisturbed pressure in chamber 51 to move the diaphragm structure and the graduated-release valve upwardly to non-release position. The amount of pres sure necessary in chamber 174. will be dependent upon the amount of increase of pressure in chamber 53. hen the valve 177 is moved upwardly to non-release position air will flow from chamber 174 through the restricted passage 186 'mto the passage 182 and thence to atmosphere through port 185. The pressure in chamber 174: will be reduced to such an entent't'hat the pressures in chart bers 53 and 173 will again force the valve 17'? to release position. Pressure will again flow to atmosphere from chamber 11 3 and will be again built up in chamber 174: and the valve .177 will be again moved back to nonrelease position. This operationwill continue until the pressure in chamber 173 has been so reduced that the combined pressures in chamber .53 and 173 are not suiheient to move the valv to release position. The valve will then remain in non-release position with the passage 119 closed thereby trapping the pressure in chamber 173.

The increase of pressure in chamber depends upon the increase of pressure in chamber :6. It is, therefore, clear that when effecting a partial release of the brakes the extent of the increase of brake pipe pressure Will determine the amount of pressure. exhausted from the control chamber '71 .and the brake cylinder 13 and the brake cylinder pressure chamber 83.

The equalizing diaphragm dis so proaort'ioned with res Ject to the actuatiiw din phragm 0 and o release diaphragm e that t-herelease otbrake cylinder pressure will be ata ratio or tWo-and-one-halt to one, that is to say for a fivepound increase of pressure in chamber 53 there will be a twelve-and-one-halt-pound reduction in brake cylinder pressure. This ratio is the same as the ratio of brake cylinder pressure built up for a given brake pipe reduction as hereinbefore described.

it is dsired to make a further partial re ction in' brake cylinder pressure the brake-pipe. pressure is again increased a predetermined amount. This will result in an increase of pressure in chamber 53 and the diaphragm structure and the graduated-release valve Will be again moved to release position. Airwill flow from chamber 173 I to atmosphere as previously described, and the pressure in chambers 71 and 83 and inthe brake cylinder B will be reduced. Air Will also rlow through the restricted port 'der pressure, will be equal to the pressure iped in chamber 173 and the release valve -ill be moved to lap position. It it now desired to increase the brake cylinder iressure the brake pipe pressure is again reduced. This will result in connecting the en'iergeney valve chamber 31 and the volume chamber to the control chamber and air will flow into the control chamber until the pressure in cha nber 31 has been sufiiciently reduced to permit the brake pipe pressure in chamber 28 to force the emergency valve back to lap position thereby interrupting the low of air to the control chamber. It-is to be noted, that this flow of air to the control chamber will be on top of the pressure trapped in the control chamber by the movement of the valve 177 to non-release position. This will result in building up a higher pressure in the control chamber than would ordinarily result from the given brake pipe reduction. The brake cylinder pressure Will then be built up to equalize with the increased pressure in the'cont-rol chamber and the brake cylinder pressure Will be at a greater ratio than tWo-and-one-half to one.

The purpose of permitting air to flow int-o ch er 1% is to provide means for maint q the bralte cylinder pressure, and the c rel chamber pressure, higher than the pr termined tWO-EiIlCl-ODQdiillf to one ratio during cycling operations. As is Well known, cycling consists of rapidly alternating applications and releases and is usually resorted to when the train is travel d If he cyclinqoperations ith :a considerable period bctween the application and release operations,- the pressure in chamber 17s will blow down; and if the periods are the pr e use in nber 174 will. be red c pressure. When, however, thecyclin operations are rapid, as when the train is rareling doun .a heavy grade, a certain amount of pressure Will be retained in chamber 17%. This retained pressure opposes the pressure retained in chamber i, While pres .e is retamed 111 chamber 171, another rel so is the pre re retained in c er on this second release will be h the amount rctainedtherein on release. This will result in retaining the same high pressure inthc control chamber in the brake c-ylii ()n the next application the pressure built up the control chamber 71 will be incr ased resulting in a. still further intn I first ler press re chamber crease in the brake cylinder pressure. As hereinbetore stated, however, it the cycling operations are slow the pressure in chamber 1.74 will blow down to atmospher and then the graduated release valve will retain brake cylinder pressure at the ratio of two-and-onchall to one in graduated release operations.

The brake cylinder pressure may be duccd in steps by increasing the brake p pe pressure in steps When it is desired to secure a full slow release the brakes the brake pipe pressure is increased to normal running preset .t

This will result in an increase oi pressure in chamber equal to the pressure in chamber 51, and the graduatedrelease valve will remain in release position untilthe brake cylinder pressure has been entirely exhausted through chamber 173. The pressures will tend to equal zae on opposite sides of the diaphragm (Z sen securing a full slow release of the brah c l or pressure, but because of the high pressure in chamber 58 equal to the pressure 111 chamber 51, the valve 177 will remain in release position, the spring 178 havingno effect upon the valve when it is moved down lease position. The pressure in both hers 173 and 174 will thereto-re tlow mosphere until there has been a coiplet 1 lease or brake cylinder and. control chamber Emergency application.

An emergency application of the brakes is e! ected by an emergency reduction. of brake pipe pressure in the usual manner. An emergency reduction of brake pipe pressure in chamber 12 will result in a corresponding reduction of pressure in Cl'lttt'l'lbQI' and chamber 28. The reduction in chamber 5 will result in the main slide valve and the graduating valve moving to service position. The reduction of pressure in chamber 2-8 will result in the emergency valve 82 moving to emergency position, as shown in Fig. 4. The emergency valve in. moving to emergency position first uncovers port 59 and this results in an equalization of pressures from cl embers and 31 into the control chamber 71. The pressure in chamber 71 moves the diaphragm structure upwardly and opens the application valve 89. and holds it open until there has been equalizc 'in of pressures from chamber G into the b. ake cylinder B, whereupon there will be an equalization of pressures in chambers 83 and 71 and the application valve will be closed as hereinbefore described.

The movement of the emergency piston 29 to emergency position will cause the collar from chamber C through passages and 187, to chamber 188 above the ch clrvalve 75. \Vhen said check valve is unseated air may flow from chamber 188 directly into the emergency valve chamber 31. The movement t the emergency valve to emergency 'ion uncovers an emergency port 189, 3n port is connected by a passage 190 to chamber 191 of the emergency pilot valve 192. Copneetcd to this valve is a pilotvalve piston 193, said piston being subject on one side to the pressure in chamber 191 and on its opposite side to the pressure in cl'iamber 19 A spring 195 normally holds the pilot valve 192 and its connected piston in their inner positions so that the pilot valve will uncover an atmospheric port 196. 'lhisport in the normal position of the pilot valve, connects chamber 191 to atmosphere. The pressure flowing into chamber 191 moves the piston 193 outwardly against the tension of spring: 195 and causes the pilot '\"alve to close the atmospheric port 196. Air will flow from chamber 191 through passan e 197 into chamber-198.

co'nected to one arm of a bellcrank lever 5299. The other arm of said lever is adapted to engage the emergency brake pipe vent valve 201 and 1 it from its seat. Valve 291 is arranged in brake pipe chamber 12 and when said valve is raised from its seat said chamber open direct to atmosphere through the large exhaust port 202. The valve 2 1. normally closes said exhaust port. The piston 199 will be moved'by the air flowing into chamber 198 from chamber 191. A port will be uncovered by the pilot valve 199 and said port is connected by passage 20-! to chamber 1.94 to permit an equalization of pressure on opposite sides of the piston 193. hen these pressures have equalized sprin 195 will move the pilot valve to closeport 20S and open port 196. Air will then flow from chambers 198 and 191 to atmosphere and spring; 205 will move the valve 201 will be closed by it-sspring. Pas- 204 is connected by passage 206 and passage 124:, this latter passage being connected to the brake cylinder pressure chambe 83 throughpa-ssae e 92 so that should the pi; cure in chamhlr 191 be higher than the brake cylinder pressure in chamber 89, there will be an equalization of said pressures through the passages just noted. In passage is arranged a check valve 208 which toward the port 293 to prevent air 7 "me; from the chamber 83 back to chamher 191.

Chamber of the equalizingr-valve and the equalizing valve chamber 57, are conn cted by passage 54=t0 the brake pipe pas 13 and. through said PfIS1gO, are open to the bralce p pe chamber 12. When the brake pipe vent valve 201,1s open the pres V In said chamber 18 arranged a piston 199 which is sure in chambers 55 and 57 will be reduced and the equalizing piston will be forced upwardly by the pressure in chamber 113. The upward movement of the equalizing valve 114 will uncover port 115 and permit air to flow from the emergency valve chamber 31 through passage 32 and 116, past check valve 117 through port 115 into chamber 57 and thence through passage 1- to the brake pipe passage 13, and thence to atmosphere through brake pipe chamber 12. At this time chamber C is connected to the emergency valve chamber 31 through passages 26, 18?,past check valve 75 and thence to chamber 31. By this means the pressure remaining in chamber C, after equalization into brake cylinder B, will be exhausted to atmosphere.

When the pressure from chamber C has been vented to atmosphere the pressure in chamber D and in the connected reservoir will expand and force the piston 35 into the chamber C and eXert its force on the braking devices, and this force will be added to the force exerted through the piston vof cylinder B.

After the pressure from chamber C has equalized into the chamber 83 and the brake cylinder B the application valve 82 will close. Shoult there be any lea-kaa'e of air from chamber 83 past valve 82, after the chamber C has beeif exhausted to atmosphere, the check valve 209 in passage 80 will prevent said air flowing back to chamber C. Any leakage from chamber 83 or from the brake cylinder B will result in an upward movement or" the release valve into position to cover the port 102 so that communication between passages 80 and 101 and the brake pipe passage 13 will be closed.

hat I claim is:

1. An air brake apparatus comprising a single chamber brake cylinder. a double chamber brake cylinder, a movable piston in the double chamber cylinder dividing said cylinder into a'service chamber and an emer gency chamber, main and graduatingslide valves, operating pistons connected thereto, an application valve provided with a control chamber and a brake cylinder pressure chamber, an emergency valve, a volume chamber connected to the emergency valve chamber, means whereby the emergency valve in service position and the main and graduating valves in service position will connect the emergency valve chamber and the vol ume chamber to the control chamber of the application valve to build up a pressure in the control chamber in direct ratio to the brake pipe reduction, means whereby the pressure in the control chamber will open the application valve to permit airto flow from the cl nnber cylinder through the application valve into the brake cylinder pressure chamservice chamber of the double her or" the application valve and from said chamber to the single chamber brake cylinder, and means whereby when the pressure in the brake cylinder chamber of the application valve equals the pressure in the control chamber the application valve will close.

2. An air brake apparatus of the Kunze Knorr type, comprising an application valve provided with a control chamber and abrake cylinder pressure chamber, means operating upon a reduction of brake pipe pressure to connect an air supply to the control chamber ot the application valve to build up a pressure in the control chamber in direct ratio to the brake pipe reduction, means whereby the pressure in the control chamber will open the said application valve to permit air to flow from the service chamber of the double chamber cylinder into the brake cylinder pressure chamber or" the application valve and into the single chamber brake cylinder, and means whereby when the pressure in the brake cylinder pressure chamber of the application valve substantially equals thepressure in the control chamber the application valve will close.

3. An air brake apparatus of the Kunze Ilnorr type, comprising an application valve irovided with a, control chamber and a brake cylinder pressure chamber, means operating upon a reduction of brake pipe pres-- sure to connect an air supply to. the control chamber of the application valve to build up a pressure in the control chamber equal to the desired brake cylinder pressure, means whereby the pressure in the control chamber will open the said application valve to permit to flow from the service chamber of the double chamber cylinder into the brake cylinder pressure chamber of the application valve and into the single chamber brake cylinder, and means whereby when the pressure in the brake cylinder pressure chamber of the application valve substantially equals the pressure in the control chamber the application valve will close.

1. An air brake apparatus comprising a single chamber brake cylinder, a double chamber brake cylinder, a movable piston in the double chamber cylinder divid ng said cylinder into a service chamber and an emergency chamber, main and graduating slide valves, operating pistons connected thereto, an application valve provided with a control chamber and a brake cylinder pressure chamber, an emergency valve, a volume chamber connected to the emergency valve chamber, means whereby the emergency valve in service position Will connect the emergency valve chamber and the volume chamber to the control chamber of the ap plication valve to build up a pressure in the control chamber in direct ratio to the brake pipe reduction, means whereby the pressure in the control chamber will open the application valve to permit air to flow from the service chamber or the double chamber cylinder through the application valve into the brake cylinder pressure chamber of the ap plication valve and from said chamber to the single chamber brake cylinder, means whereby when the pressure in the brake cylinder chamber of the application valve equals the pressure in the control chamber the application valve will close, and an equalizing valve subject to brake pipe and control chamber pressures and operating upon a reduction 01' brake pipe pressure below the control chamber pressure to connect the volume chamber and the emergency valve chamber to the brake pipe.

5. An air brake apparatus comprising a single chamber brake cylinder, a double chamber brake cylinder, a movable piston in the double chamber cylinder dividing said cylinder into a service chamber and an emergency chamber, main and graduating slide valves, operating pistons connected thereto, an application valve provided with a control chamber and a brake cylinder pressure chamber, an emergency valve, a volume chamber connect-ed to the emergency valve chamber, means whereby the emergency valve in service position will connect the emergency valve chamber and the volume chamber to the control chamber of the application valve to build up a pressure in the control chamber indirect ratio to the brake pipe reduction, means whereby the pressure in the control chamber will open the application valve to permitair to flow from the service chamber or' the double chamber cylinder through the application valve into the brake cylinder pressure chamber of the application valve and from said chamber to the single chamber brake cylinder, means whereby when the pressure in the brake cylinder chamber of the application valve equals the pressure in the control chamber the application valve will close, an equalizing valve subject to brake pipe and control chamber pressures and operating upon a reduction of brake pipe pressure below the control chamber pressure to connect the volume chamber and the emergency valve chamber to the brake pipe, and means whereby an emergency reduction of brake pipe pressure will connect the said service chamber to atmosphere.

6. An air brake apparatus of the Kunze Knorr type, comprising a single chamber brake cylinder, a double chamber brake cylinder, a movable piston in the double chamber cylinder dividing said cylinder into a service chamber and an emergency chamber, and means operating upon a reduction of brake pipe pressure to connect the said service chamber to the single chamber brake cylinder to build up in said brake cylinder a pressure at a. predetermined ratio to the brake pipe reductionwithout regard to the length of brake cylinder piston travel. 7

7. An air brake apparatus of the Kuuze Knorr type, comprising a single chambr brake cylinder, a double chamber brake cylinder, a movable piston in the double chamber cylinder dividin said cylinder into a service chamber and an emergency chamber, means operating upon a reduction of brake pipe pressure to connect the said service chamber to the single chamber bruit cyl inder to build up in said brake cylinder a pressure at a predetermined ratio to the brake pipe reduction without regard to the length of brake cylinder piston travel, and means adapted to operate when the service chamber of the double chamber brake cylinder has been equalized into the single chamber brake cylinder to prevent the air remaining in the said service chamber flowto atmosphere when the brake pipe pressure is reduced below said point or equalization.

8; An air brake apparatus of the Kunze Knorr type, comprising an application valve provided with a control chamber and a brake cylinder pressure chamber, means operating upon a reduction oi brake pipe pressure to connect an air supply to the control chamber of the application valve to build up a pressure in the control chamber equal to the desired brake cylinder pressure, means whereby the pressure in the control chamber will open the said application valve to permit air to flow from the service chamber of the doublechamber cylinder into the brake cylinder pressure chamber of the application valve and into the single chamber brake cylinder, means whereby when the pressure in the brake cylinder pressure chamber of the application valve substantially equals the pressure in the control chamber the application valve will close, and means adapted to operate when the service chamber of the double chamber brake cylii'ider has been equalized into the single chamber brake cylinder to prevent the air remaining in the said service chamber flowing to ati'uosphere when the brake pipe pressure is reduced below said pomt o't equalization,

9. An air brake apparatus of the Kunze.

inder, and means adapted to operate when the service chamber of the double chamber brake cylinder has been equalized into the single chamber brake cylinder to prevent the air remaining in the said service chamber flowing to atmosphere when the brake 

